Poster B6 - A low-cost, parafilm©-based, 3D microfluidic platform for cell screening

Thursday, October 24, 2024

10:00 AM - 11:00 AM EST

Location: Exhibit Hall E, F & G

Presenting Author(s)

Daniel Gendy (he/him/his)

Undergraduate Researcher at NJIT
New Jersey Institute of Technology
Fairfield, New Jersey, United States

Co-Author(s)

MM

Mohaddeseh Mohammadi

PhD Student
New Jersey Institute of Technology, United States
SB

Sagnik Basuray

Assistant professor
New Jersey Institute of Technology, United States

Primary Investigator(s)

AM

Amir Miri

Assistant professor
New Jersey Institute of Technology, United States

Introduction: Parafilm-based Microfluidics technologies enable affordable, customizable, and high-throughput platforms suitable for individual lab use. Parafilm is disposable, eliminating the need for complex cleaning and sterilization biological processes, and requires very low volumes of reagents and cells. Here, we describe a novel low-cost microfluidic cell sorter that operates in continuous flow at high sorting rates. The spiral inertial microfluidic device can achieve label-free, continuous separation of cell mixtures with high throughput and efficiency. The device utilizes hydrodynamic forces acting on cells within a laminar flow coupled with rotational drag due to the curvilinear microchannel geometry. A mixture of cells can be sorted directly from bulk media without encapsulation, contrasting agents, fluorescent tags, or labeling. We have successfully directed MDA-MB-231 (breast cancer cells) using the low-cost (~ $5) microfluidic chip. Cell sorting on microchips provides numerous advantages over conventional methods by reducing the size of necessary equipment, eliminating potentially biohazardous aerosols, and simplifying the complex protocols commonly associated with cell sorting. Microfluidic platforms have traditionally been created using Polydimethylsiloxane (PDMS). PDMS takes on the shape of its mold, has high optical transparency for imaging, and is highly elastic. However, the porosity of PDMS leads to the absorption of reagents, and this may not only affect optical transparency but also decrease reagent concentration over time. Much time and labor goes into creating PDMS based microfluidic devices. There is, thus, a need to create microfluidic platforms out of alternative polymeric materials while maintaining the same low-cost and transparent benefits of PDMS.

Materials and

Methods: We report a double layer parafilm microfluidic platform with a total fabrication time of 20-30 minutes. A laser cutter (Universal Laser Systems PLS660 50 Watt Laser) is used to create microchannels in a top parafilm layer while leaving a bottom parafilm layer intact. Linear channels are made using 0.9 power and 0.9 speed, while multiple horizontal lines are made for wide shapes using 60 power and 75 speed. These laser parameters are optimal for cutting through single-layer parafilm sheets while leaving the bottom layers intact. A drill press from central machinery and diamond tip drill bits are used to create inlet and outlet ports within a glass slide, which is aligned and placed onto the inlet and outlet ports of the parafilm chip. This glass + parafilm + glass microfluidic platform is heated to 55 °C for 15 minutes in an oven, and binder clips are clipped onto the sides of the microfluidic chip to promote parafilm + glass bonding and prevent leakage. Silicon-based tubing is connected to a syringe pump set to 10 μl/min, and a solution of DI water and food color is pumped through the parafilm microchannels. The proposed 3D geometry allows for precise manipulation and analysis of cell populations within a controlled microfluidic environment. The channel size was in the range of 100 to 1000 micrometers. We used Rhodamine B dye (0.012M) to visualize the overlapping channels in the different parafilm layers. OCT4-GFP tagged MDA-MB-231 cells were seeded in the microchannels.

Results, Conclusions, and Discussions: In this study, we chose a laser cutter over a plotter cutter for fabricating microchannels in Parafilm® sheets. The precision offered by the laser cutter is crucial, as the dimensions of the channels directly impact the volumes of samples and reagents needed for assays. The two layers of the low-cost parafilm-based microchip were tightly sealed after heat and pressure treatment, and the inlet and outlets were connected to tubes using superglue to complete the microfluidic setup. The infusion of dye showed well-formed complex geometries along with capability for flow within different vertical planes. A continuous flow of both the dye and cell solution was observed from the layers. The high concentration of cells allowed for effective sorting due to the spiral geometry and separation by the trident channel design. This research validated the practical application of a low-cost microfluidic chip using Parafilm® sheets. The findings substantiate the feasibility and accuracy of employing laser cutting technology for detailed microfabrication tasks, highlighting its potential for economical and precise microscale patterning.

Acknowledgements (Optional):